4–32

Using Intelligent Input Terminals

The speed control mode is normally proportional- integral compensation (PI), which attempts to keep the deviation between the actual speed and speed command equal to zero. You can also select proportional (P) control function, which can be used for droop control (i.e. several inverters driving one load). Droop is the speed difference

P Control

PI Control

Torque

resulting from P control versus PI control at 100% output torque as shown in the graph. Set the P/PI switching function (option 43) to one of the intelligent input terminals [1] to [8]. When the P/PI input terminal is ON, the control mode becomes proportional control (P). When the P/PI input terminal is OFF, the control mode becomes proportional-integral control.

100%

0

Droop

Speed of rotation

The proportional gain Kpp value determines the droop. Set the desired value using parameter

H052. The relationship between the Kpp value and the droop is shown below:

Droop =

10

(%)

(Kpp-------------------------------Set Value)-

The relationship between the droop and the rated rotation speed is shown below:

Droop =

Speed error at rated torque

Synchronous---------------------------------------------------------------------speed base frequency

Operations and Monitoring